Mycologia, 100(3), 2008, pp. 490–495. # 2008 by The Mycological Society of America, Lawrence, KS 66044-8897

New species of Boletellus from Guyana

Tara D. Fulgenzi mirabilis (Murrill) Singer) as well as those with Department of Biology, Humboldt State University, longitudinally striate spores. Smith and Thiers Arcata, California 95521 (1971) argued against Singer’s broad concept of the Jordan R. Mayor genus and included only species with spores that are Department of Botany, University of Florida, longitudinally winged, ridged or striate; by doing so Gainesville, Florida 32611 Boletellus can be determined easily microscopically and is consistent with the type species’ morphology 1 Terry W. Henkel (Smith and Thiers 1971). Corner (1972) and Pegler Roy E. Halling (1983) also adhered to a narrower definition of Institute of Systematic Botany, New York Botanical Boletellus characterized by spores that are longitudi- Garden, Bronx, New York 10458 nally winged, ribbed, costate or striate. Here we describe Boletellus exiguus sp. nov. and Boletellus dicymbophilus sp. nov. discovered in ectomy- Abstract: Boletellus exiguus sp. nov. and Boletellus corrhizal (EM) Dicymbe (Caesalpiniaceae) forests in dicymbophilus sp. nov. (, , Basidio- Guyana. These two new species are placed in Boletellus mycota) are described as new to science. These based on their olivaceous brown, longitudinally ridged boletes were collected from tropical forests dominat- basidiospores, dry pilei, tubulose, blue-staining hyme- ed by ectomycorrhizal Dicymbe corymbosa (Caesalpi- nophores and lack of clamp connections. niaceae) in the Pakaraima Mountains of western Guyana. Key words: Boletaceae, Dicymbe, ectomycorrhizal MATERIALS AND METHODS fungi, Guiana Shield, neotropics Annual collecting expeditions were conducted during the rainy seasons (May–Jul) 1998–1999 in the Upper Ireng River INTRODUCTION Basin along Guyana’s western border with Brazil in the west- central Pakaraima Mountains, and 2000–2005 in the Upper The genus Boletellus Murrill (Boletaceae, Boletales, Potaro River Basin , 30 km north of the Ireng site. At each ) encompasses , 44 described species site fungi were collected within a 5 km radius of a previously worldwide, the majority with tropical distributions established base camp in forests dominated by Dicymbe (Heinemann and Goossens-Fontana 1954, Snell and corymbosa Spruce ex Benth. (Henkel 2003). Dick 1970, Smith and Thiers 1971, Corner 1972, Basidiomata were examined in the field for their fresh Horak 1977, Singer 1986, Singer et al 1992, Watling characteristics. Color was subjectively described and record- 2001, Halling and Mueller 2005, Ortiz-Santana et al ed according to Kornerup and Wanscher (1978) with color plates noted in parentheses (e.g. 3C4). Macrochemical spot 2007). Boletellus has been variably defined, yet all tests were performed following Singer (1986). Basidiomata definitions have in common these features: basidio- were field-dried with silica gel beads. spores that are olivaceous brown in deposit, a yellow Microscopic anatomical details were determined on fresh hymenophore becoming olivaceous with time and specimens at base camp with an EPOI microscope and in boletoid (i.e. strongly divergent) tube trama. Despite the laboratory with an Olympus BX51 microscope with these commonalities individual author concepts vary. bright field and phase contrast optics. Fungal tissue of dried Singer (1986) adhered to a broad definition of specimens was rehydrated and mounted in either H2O, 3% Boletellus by including species with longitudinally KOH, or Melzer’s reagent. For each taxon a minimum of 20 winged or ridged spores (sections Boletellus, Chrysen- basidiospores, basidia, cystidia and other structures were teroidei, Ixocephali and Dictyopodes), smooth spores measured. Line drawings were made with a drawing tube, (section Mirabilis), spores with imbedded short inked and scanned. Scanning electron micrographs of basidiospores were obtained with either a Jeol JSM-6400 or spines or pits (section Allospori) and reticulate spores Topcon ABT32 scanning electron microscope using 200 kV. (section Retispori). Heinemann (1951) and Snell and Specimens are deposited in these herbaria as indicated: Dick (1970) included species that have spores with BRG, HSU and NY (Holmgren et al 1990). imbedded short spines or pits (e.g. Boletellus purpur- ascens Heinem.), smooth spores (e.g. Boletellus

Accepted for publication 19 March 2008. Boletellus exiguus T.W. Henkel and Fulgenzi sp. nov. 1 Corresponding author. E-mail: [email protected] FIGS. 1–2, 5a, b

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FIG. 1. Basidiomata of Boletellus exiguus (HOLOTYPE; Henkel 8696). Bar 5 10 mm.

Pileus brunneus, juventute velutinus, postea subtiliter chestnut brown (5D5–5E7) to yellow-tan (4E6) with areolatus, 9–33 mm latus. Trama caerulescens ubi exposita. age, velutinous, becoming finely squamulose and Stipes brunneus, subtiliter longitudinaliter striatus, cartila- areolate when mature, less so over disk, tacky to dry; gineus, apice cum collo rubro, 7–34 3 1–4 mm. Basidio- margin slightly inrolled when young, irregularly sporae olivaceae in massa, amygdaliformes, longitudinaliter crenulate with age; trama 1–1.2 mm thick at margin, porcatae, 10–15 3 7–9 mm. Fructificatio insidens trunco 1–2 mm over tubes, 2–2.5 mm over stipe, dingy-white, Dicymbe arborum. HOLOTYPE: Henkel 8696 (BRG; ISOTYPE: HSU, NY; bluing rapidly with exposure, solid, less so with age. MycoBank No. MB 511183) Odor minimal, pleasant; flavor mild. Tubes 1–2 mm Pileus 9–33 (42) mm broad, convex to applanate, long at margin, 2–7 mm centrally, 2–5 mm at stipe, dark brown (7D7) throughout when young to broadly and shallowly depressed around stipe, of irregular lengths, concolorous with pores, rapidly blue-green (26E7) on exposure; pores lemon yellow (3A7) when young, maturing to olive-yellow (4C7– 4C8), rapidly blue-green (26E7) with pressure, with prominent decurrent tooth 2–2.5 mm long, 0.5–2 per mm, subangular, radially elongate near stipe. Stipe 7– 34 3 1–4 mm, subequal, gradually and slightly flaring to 2–4 mm at apex and base, typically curving outward and upward from Dicymbe trunk, cartilaginous, tan (5D6) to maroon-brown (10F6–10D8) throughout, with prominent red (10D8) zone over distal 1–2 mm of apex, darkening slightly with handling, finely longitudinally striate; extreme base with brown tomentum; trama red-maroon (10F6–10F8) in upper half, tan-brown (5D5) below, unchanging. Basidiospores olivaceous-brown (5F6–6F5) to dark olive-green (3F8) in medium to heavy deposit, 10–15 FIG. 2. Microscopic features of Boletellus exiguus (HO- 3 7–9 mm (mean 12.7 3 8.2 mm; n 5 20), Q range 5 LOTYPE; Henkel 8696). a. Basidia. b. Pleurocystidia, in 1.2–2, (mean Q 5 1.53), olive-golden in H2O and Melzer’s. c. Basidiospores. Bar 5 10 mm. KOH, inamyloid, amygdaliform, with moderately

Mycologia myco-100-03-13.3d 19/6/08 14:07:41 491 Cust # 07-170R 492 MYCOLOGIA thick single wall, uniguttulate, with 10–16 longitudi- within 5 km radius of 5u18904.80N, 59u54940.40W, elevation nal ridges; ridges , 1 mm tall, occasionally bifurcat- 710–750 m; vicinity of Potaro base camp, 26 May 2000, ing, terminating at unequal lengths before the apex Henkel 7436 (BRG; HSU); 3 km southwest of Potaro base and thus leaving a smooth area, all ridges converging camp near Dicymbe plot 3, 29 Jul 2003, Henkel 8636 (BRG; HSU); in Dicymbe plot 3, 24 Jun 2004, Henkel 8696 at hilar appendage; hilar appendage 0.5–1 mm long. (HOLOTYPE, BRG; ISOTYPE: HSU, NY); 1 km southeast Basidia 37–51 3 12–15 mm, subclavate, tapering of Potaro base camp, 28 May 2005, Henkel 8809 (BRG; gradually to base, hyaline in H2O and KOH, with HSU); 1 km west of Potaro base camp, 30 May 2005, Henkel numerous refractive globules pale yellow in H2O, 8815 (BRG; HSU). lighter in KOH, with three or four sterigmata; Commentary. Boletellus exiguus is recognized in the sterigmata 2–4 mm long. Pleurocystidia infrequent, field by its diminutive size, the chestnut-brown, 65–85(100) 3 14–20 mm, projecting 27–42 mm above squamulose and finely areolate pileus, irregularly the hymenial palisade, ventricose, thin-walled; wall angular pores that are lemon-yellow when young, hyaline in H2O and KOH, with golden incrustations rapidly blue-staining hymenophore, a red zone at the evident in Melzer’s. Hymenophoral trama boletoid, apex of a small curving stipe, and the habit of fruiting strongly divergent; mediostratum 37–54.3 mm wide, of alone or in small groups on Dicymbe trunks. The many thin, slightly interwoven hyphae, these hyaline masses of humus that accumulate between the in H2O, gelatinized and hyaline in KOH, lateral epicormic shoots and roots of mature Dicymbe trees stratum hyphae 6.2–9.8 mm wide, hyaline in H2O and appear to be a required site for fruiting of B. exiguus KOH, nongelatinized. Pileipellis a derm consisting of and are known to harbor abundant ectomycorrhizae angular cells with tufts of erect inflated terminal cells (Woolley et al 2007). A similar fruiting habit has been concentrated in the squamules; tufts 91.4–197.6 mm noted elsewhere for other Boletellus spp. (e.g. Boletellus wide, in mass orange-yellow in H2O, paler in KOH; emodensis [Berk.] Singer, Boletellus ananas [M.A. terminal cells 19.7–41.2 mm long, cylindrical or Curt.] Murrill; Corner 1972, Singer et al 1983) and ventricose, rarely clavate or mucronate. Pileus trama also is recorded here for Boletellus dicymbophilus sp. interwoven; individual hyphae 6.1–11 mm wide, light nov. Microscopically B. exiguus is distinguished by golden in H2O, hyaline in KOH, regularly septate. having three or four sterigmate basidia with numerous Stipitipellis a densely interwoven trichodermial pali- pale yellow refractive globules, pleurocystidia with sade of cylindrical elements with inflated terminal golden incrustations in Melzer’s, and a pileipellis of cells, in mass golden-orange in H2O, lighter in KOH; angular cells with tufts of erect inflated terminal terminal cells projecting 24.7–38.3 mm, cylindrical to elements. ventricose, concentrated on stipe striations. Stipe Boletellus exiguus is best disposed infragenerically in trama of densely interwoven hyphae, these 2–4.9 mm Boletellus section Chrysenteroidei Singer based on the wide, faint golden in H2O, hyaline in KOH. Clamp absence of red tints on the pileus, the general lack of connections absent. Macrochemical reactions: NH4OH viscidity and the absence of a marginal veil (Snell and immediately blood-red (9C8) on pileus, then fading Dick 1970, Singer 1986). The diminutive size of B. within minutes to orange, negative on stipe and exiguus is similar to that of the boletelloid Boletus pores; KOH red-orange (9B8) on pileus then quickly ridiculus Corner from Malaysia; B. ridiculus however becoming orange (6B8), red (8D8) on stipe; FeSO4 can be distinguished from B. exiguus by its longer negative on pileus, dark blue-green (25F4) on tube basidiospores (16–21 mm vs. 10–15 mm) and shorter mouths then fading to a dark olive-green (26F5), pleurocystidia (40–60 mm vs. 65–85[100] mm) (Corner darkening stipe. 1972). The distinctive red zone at the stipe apex of B. Habit, habitat, and distribution. Solitary to scattered exiguus resembles the red annular band of Boletellus among humic accumulations on trunks of large, living cubensis (Berk. & M.A. Curt.) Singer from the eastern Dicymbe corymbosa trees; known from the type locality Caribbean, but B. exiguus lacks an annulus; B. in the Upper Potaro River Basin and adjacent Upper cubensis is also markedly larger (pileus 20–60 mm vs. Ireng River Basin of Guyana. 9–42 mm diam, stipe 30–70 mm vs. 7–34 mm long; Etymology. Exiguus 5 small (Latin), referring to the Pegler 1983, Singer et al 1983). Among Congolian diminutive basidiomata. Boletellus spp. none are phenotypically close to B. Specimens examined. GUYANA. REGION 8 POTARO- exiguus (Heinemann and Goossens-Fontana 1954). SIPARUNI: Pakaraima Mountains, Upper Ireng River Basin; Other members of Boletellus that deviate from strictly 1.5 km east of confluence of Sukabi and Ireng rivers, lower slope of Mount Kukuinang, elevation 850 m, 6 Jun 1998, 4-sterigmate basidia are Boletellus jalapensis (non Henkel 6898 (BRG; HSU); west bank of Yuarka Creek, 1 km sensu Murrill) Gilbert, and Boletellus obscurecoccineus upstream from confluence with Suruwabaru Creek, eleva- (Ho¨hn) Singer, but otherwise these species do not tion 800 m, 31 May 1999, Henkel 7088 (BRG; HSU), 15 Jun phenotypically resemble B. exiguus (Corner 1972, 1999, Henkel 7208 (BRG; HSU); Upper Potaro River Basin, Singer et al 1983).

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FIG. 4. Microscopic features of Boletellus dicymbophilus (HOLOTYPE; Henkel 8616) a. Basidia. b. Pleurocystidia. c. Basidiospores. Bar 5 10 mm.

isodiametric to angular with age. Stipe 41–60 (81) 3 4–7 mm, equal, slightly enlarging at extreme base, red-brown (9D7–9E7) throughout, with handling FIG. 3. Basidiomata of Boletellus dicymbophilus (Henkel becoming brown (7F6–7F7) to dark brown (8F5), 8818). Bar 5 10 mm. finely longitudinally striate throughout, striations minutely pubescent (under lens), subreticulate at Boletellus dicymbophilus Fulgenzi and T.W. Henkel apex, base with brown (8F5) strigose hairs on lower 4– 20 mm; trama brown (6E7–6F7) throughout to dark sp. nov. FIGS. 3–4, 5c Pileus porphyreus, convexus vel planus, rugosus, veluti- brown (7F7) to red-brown (8E4), unchanging, solid. nus, postea subtiliter areolatus, 19–48 mm latus; trama alba, Basidiospores olive (4D6) to olivaceous brown (4F7) immutabilis. Stipes brunneus, longitudinaliter striatus, ad in light to heavy deposit; 12–15 3 8–11 mm (mean 5 tactum atrans, 41–60(81) 3 4–7 mm. Basidiosporae oliva- 13 3 9 mm; n 5 25), Q range 1.2–1.7 (mean Q 5 ceo-brunneae in massa, amygdaliformes, longitudinaliter 1.37), golden-olive in H2O and KOH, inamyloid, porcatae, 12–15 3 8–11 mm. Fructificatio insidens trunco amygdaliform, usually uniguttulate, with 7–10 longi- Dicymbe arborum. tudinal ridges; ridges , 1 mm tall, dichotomously HOLOTYPE: Henkel 8616 (BRG; ISOTYPE: HSU, NY; forked, occasionally nonforked, terminating in un- MycoBank No. MB 511184) equal lengths near apex, at extreme base all ridges Pileus 19–48 (82) mm broad, convex to planocon- converging at hilar appendage; hilar appendage 1– vex, red-brown (8E8–9E8–9F5) when immature, 1.5 mm long. Basidia 43–48 3 12–15 mm, clavate, thin- becoming brown (6E6–6F6) and then orange-tan walled, hyaline in H2O and KOH, with numerous (6C6) to yellow-tan (4C6) with age, rugulose to refractive globules, these light golden in H2O, lighter rugose throughout, velutinous, finely areolate with in KOH; with 2, 3 or 4 sterigmata. Pleurocystidia age (under lens), moist, margin slightly inrolled and frequent, 33–56 3 7–12 mm, projecting 22–49 (57) entire; trama 1–3 mm thick at margin, 2–5 mm over mm beyond the hymenial palisade, arising from the tubes, 3–7 mm above stipe, white to cream, slightly subhymenium, cylindrical to narrowly clavate; thin- browning with exposure, solid. Odor indistinct; flavor walled, hyaline in H2O and KOH, with minute amber mild. Tubes 1–6 mm long at margin, 5–13 mm incrustations at basal and apical portions evident in centrally, 4–8 mm at stipe, narrowly and shallowly Melzer’s and H2O. Hymenophoral trama boletoid, depressed around stipe, with short decurrent tooth 1– strongly divergent; mediostratum 37–59.3 mm wide, 2 mm long, concolorous with pores, instantly bluing of thin, slightly anastomosing hyphae, golden-orange (26E8) on exposure, eventually darkening to brown; in H2O, gelatinized and lighter in KOH; lateral pores progressing from yellow (4A7–4B7) to orange- stratum hyphae 1.2–2.5 mm wide, hyaline in H2O yellow (4C8–5D8) to dark yellow (4A8–5B8), rapidly and KOH, nongelatinized. Pileipellis a two-layered blue-green (26E7) with pressure, 0.5–1.5 per mm, trichodermial palisade, in mass golden in H2O,

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FIG. 5. Scanning electron micrographs of basidiospores of Boletellus species from Guyana. a. Boletellus exiguus (HOLOTYPE; Henkel 8696), 36700. b. Boletellus exiguus (Henkel 8809), 38900. c. Boletellus dicymbophilus (Henkel 8824), 33200. Bar 5 1 mm. lighter in KOH; terminal cells 42–76.6 3 12.4– Specimens examined. GUYANA. REGION 8 POTARO- 24.7 mm, most inflated and of variable shapes, oblong, SIPARUNI: Pakaraima Mountains, Upper Potaro River, cylindrical, napiform, vesiculate, to occasionally within 5 km radius of 5u18904.80N, 59u54940.40W, elevation bluntly ventricose; penultimate cells interwoven, less 710–750 m; Ayanganna airstrip, 20 May 2000, Henkel 7405 (BRG; HSU); Dicymbe plot 2, 8 May 2000, Henkel 7455 inflated, hyaline in H2O and KOH, inamyloid. Pileus (BRG; HSU); Dicymbe plot 2, 10 May 2000, Henkel 7480 trama interwoven; hyphae 6.2–12.4 mm wide, thin- (BRG; HSU); Dicymbe plot 2, 23 Jun 2000, Henkel 7851 walled, faint golden in H O, hyaline in KOH, 2 (BRG; HSU); vicinity of Potaro base camp, 2 May 2001, regularly septate, with external dark burgundy acer- Henkel 8011 (BRG; HSU); Dicymbe plot 1, 18 May 2001, ose crystals evident in KOH, Melzer’s, and H2O. Henkel 8152 (BRG; HSU); vicinity of Potaro base camp, 25 Stipitipellis an interwoven trichodermial palisade of Jul 2003, Henkel 8616 (HOLOTYPE, BRG; ISOTYPE: HSU, cylindrical elements giving rise to inflated terminal NY); vicinity of Potaro base camp, 5 Jul 2004, Henkel 8733 cells, in mass golden in H2O, lighter in KOH; (BRG; HSU); vicinity of Potaro base camp, 31 May 2005, terminal cells 40–66.7 (77) 3 4.9–7.4 mm wide, thin- Henkel 8818 (BRG; HSU); 1.5–2 km southeast of Potaro walled, cylindrical to aciculate; hyaline in H2O and base camp, 1 Jul 2005, Henkel 8824 (BRG; HSU); 0.5–1 km KOH, inamyloid. Stipe trama of densely packed west of Potaro base camp, 3 Jun 2005, Henkel 8829 (BRG; longitudinal hyphae, these 5–10 mm wide, hyaline in HSU); 2 km southeast of Potaro base camp, 5 Jun 2005, Henkel 8840 (BRG; HSU). H2O and KOH, with external dark burgundy acerose crystals evident in KOH, Meltzer’s and H2O. Clamp Commentary. Boletellus dicymbophilus is distinctive connections absent. Macrochemical reactions:NH4OH due to its dark red-brown, rugose pileus that becomes burgundy on pileus, orange on pileus trama, burgun- lighter with maturation, its subequal, dark brown, dy on stipe base trama; KOH burgundy to orange on longitudinally striate stipe, the yellow to olive-yellow, pileus, dark orange on pileus trama, burgundy on blue-staining hymenophore, lack of a bluing reaction stipe base trama. of the exposed trama and habit of fruiting singly or in Habit, habitat, and distribution. Solitary or in groups of 2–3 on D. corymbosa trunks. Microscopically groups of 2–3 among humic accumulations on trunks B. dicymbophilus is distinguished by its 2–4 sterigmate of large, living Dicymbe corymbosa trees; known only basidia with numerous pale yellow refractive globules, from the type locality in the Upper Potaro River Basin cylindrical to narrowly clavate pleurocystidia with of Guyana. amber encrusting pigments evident in H2Oand Etymology. Dicymbophilus 5 Dicymbe loving Melzer’s, a 2-layered palisadic pileipellis of variously (Greek), referring to the exclusive fruiting habit on shaped terminal elements, a palisadic stipitipellis of Dicymbe trunks. variably shaped cylindrical elements and the presence

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of external burgundy acerose crystals in the pileus and nian Institution’s Biological Diversity of the Guiana Shield stipe trama. Program publication series. Boletellus dicymbophilus is best disposed infrageneri- cally in Boletellus section Chrysenteroidei Singer based LITERATURE CITED on the dry pileus lacking red tints and the absence of a marginal veil (Snell and Dick 1970, Singer 1986). Corner EJH. 1972. Boletus in Malaysia. Singapore: Botanic Nonbluing trama has also been reported for Boletellus Gardens. longicollis (Ces.) Pegler & Young, B. obscurecoccineus Halling RE, Mueller GM. 2005. Common Mushrooms of the (Corner 1972) and B. cubensis (Berk. & M.A. Curtis) Talamanca Mountains, Costa Rica. New York: New York Singer (Pegler 1983, Singer et al 1983); although only Botanical Gardens Press. B. longicollis from Malaysia and Japan is otherwise Heinemann P, Goossens-Fontana M. 1954. Flore iconogra- phique des champignons du Congo. In: Fascicle 3. phenotypically similar to B. dicymbophilus, with dark . Brussels: Le jardin Botanique de l’Etat. brown rugose pilei, but the former has a well p 51–78. developed, white, gelatinous appendiculate veil (Cor- Henkel TW. 2003. Monodominance in the ectomycorrhizal ner 1972, Imazeki et al 1988). Other members of Dicymbe corymbosa (Caesalpiniaceae) from Guyana. J Boletellus that deviate from strictly 4-sterigmate Tropic Ecol 19:417–437. basidia are B. jalapensis, Boletellus ivoryi Singer and Holmgren PK, Holmgren NH, Barnett LC. 1990. Index B. obscurecoccineus, but each differs from B. dicymbo- Herbariorum. Part I: the herbaria of the world. Reg Veg philus; for example B. jalapensis has longer basidio- 120:1–693. spores (15–25 vs. 12–15 mm) and B. obscurecoccineus Horak E. 1977. Boletellus and Porphyrellus in Papua New longer pleurocystidia (65–130 vs. 33–56 mm; Corner Guinea. Kew Bulletin 31:645–652. 1972, Singer et al 1983). Boletellus dicymbophilus is Imazeki R, Otani Y, Hongo T. 1988. Fungi of Japan. Tokyo: similar to Boletellus pustulatus (Beeli) Gilbert from Yama-Kei Publishing Co. Ltd. Kornerup A, Wanscher JH. 1978. Methuen handbook of tropical Africa in basidioma stature, basidiospore size, colour. 3rd ed. London: Eyre Methuen Ltd. and the presence of a 2-layered palisadic pileipellis of Ortiz-Santana B, Lodge DJ, Baroni TJ, Both EE. 2007. variously shaped hyphal elements. However B. Boletes from Belize and the Dominican Republic. pustulatus possesses ventricose-rostrate pleurocysti- Fungal Divers 27:247–416. dia, cheilocystidia and a bluing reaction in the Pegler DN. 1983. Agaric flora of the Lesser Antilles. Kew exposed trama (Heinemann and Goossens-Fontana Bull Add Ser 9:1–668. 1954, Watling and Turnbull 1992). Singer R, Araujo I, Ivory MH. 1983. The ectotrophically mycorrhizal fungi of the neotropical lowlands, espe- cially Central America. Beih Nov Hedweg 77:1–352. ACKNOWLEDGMENTS ———. 1986. The Agaricales in modern taxonomy. 4th ed. This research is supported by grants to TWH from the Koenigstein, Germany: Koeltz Scientific Books. National Geographic Society’s Committee for Research and ———, Garcia J, Gomez LD. 1992. The Boletineae of Exploration, the Smithsonian Institution’s Biological Diver- Mexico and Central America IV. Beih Nov Hedweg 105: sity of the Guiana Shield Program, the Linnaean Society of 1–49. London, the Duke University Department of Botany and Smith AH, Thiers HD. 1971. The Boletes of Michigan. Ann the Humboldt State University Foundation. Field assistance Arbor: University of Michigan Press. in Guyana was provided by Mimi Chin, Cathie Aime, Snell WH, Dick EA. 1970. The Boleti of Northeastern North Christopher Andrew, Leonard Williams, Valentino Joseph, America. Lehre, Germany: J. Cramer. Francino Edmond and Luciano Edmond. Micah Dunthorne Watling R. 2001. Australian boletes: their diversity and is thanked for the scanning electron micrograph of possible origins. Aust Syst Bot 14:407–416. Boletellus exiguus. REH acknowledges support from the ———, Turnbull E. 1992. Boletes from South and East National Science Foundation grant DEB-0414665. The Central Africa I. Edinburgh J Bot 49:343–361. authors thank J. Kimbrough and G. Laursen for use of Woolley LP, Henkel TW, Sillett SC. 2007. Reiteration in the laboratory facilities. Research permits were granted by the tropical monodominant tree Dicymbe corymbosa (Cae- Guyana Environmental Protection Agency and Ministry for salpiniaceae) and its potential adaptive significance. Amerindian Affairs. This paper is No. 130 in the Smithso- Biotropica 40:32–42.

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